The mediating role of health behaviors in the relationship between internal locus of control and life satisfaction in public health students

Well-being is a continuous process requiring decisions and actions to maintain or build health. This study examines the indirect effect of health locus of control on life satisfaction via healthy behaviors based on living systems theory. Participants were 730 students of various majors related to medicine and health, aged between 19 and 30 (M = 22.29, SD = 1.64), including 79.04% women. Self-report measures were used to assess life satisfaction, multidimensional health locus of control, and health behavior. Women scored higher than men on the total health behavior scale, especially in a healthy diet and preventive behavior. Men scored higher than women on internal health locus of control (HLC), while women scored higher than men on the powerful others HLC in making decisions about their health. The study confirmed the mediating effect of healthy behavior on the relationship between the internal HLC and life satisfaction. The present mechanism highlights the crucial role of internal motivation in increasing subjective well-being by maintaining health behaviors among young adults. The role of intervention programs focused on improving internal HLC and health behaviors is discussed.


Associations between healthy lifestyle and well-being
Health behaviors are shaped during adolescence as a result of socialization and many other environmental and personal factors of the individual.Bellis et al. 22 showed that risky behavior occurring in adulthood, as well as poor mental and physical health, are the result of unfavorable childhood experiences.It is worth noting that the period of undertaking higher education, namely entering adulthood and independence, also seems to be critical for the development of an individual lifestyle.Overall, risky behaviors occur much more often among adolescents and young adults than in other age groups 23 .
It is disturbing that during the COVID-19 pandemic, the health behaviors of nursing students, regardless of gender, have worsened 24 .Generally, medical students demonstrate a higher level of health-related behaviors than students of other fields of study 25 .It is known from many studies that gender differentiates individual healthrelated behaviors.Taking care of health, responsibility for one's health, and nutrition are the domain of women, while men dominate in practices related to physical activity 26,27 .Some researchers indicate that women generally provide a more healthy lifestyle than men 28 .Longitudinal research shows that the general well-being of students has recently decreased, but men have a higher level of well-being, which is related to, among others, practicing behaviors such as getting more sleep, physical activity, greater social connections, less alcohol consumption, and less activity on social media 29 .
Satisfying needs through everyday decisions shapes an individual lifestyle.Kesebir and Diener 30 claim that striving for happiness is one of the forms of a good life.In Western societies, diverse lifestyles are acknowledged, and they can often differ significantly.Among the younger population, healthy behaviors are influenced by numerous factors, including environmental challenges.One such recommended approach is a healthy lifestyle, which is characterized by a preponderance of behaviors that promote well-being over those that undermine it 31 .Health behaviors are any actions taken to prevent, detect disease, or improve health and well-being 32 .
The impact of healthy behaviors on life satisfaction has been the subject of extensive research.Life satisfaction, a critical cognitive component of subjective well-being, is influenced by various factors, including health behaviors 33 .In particular, regular physical activity is consistently associated with higher life satisfaction across different populations, including health professionals, older adults, and the general population [34][35][36][37][38][39] .Also, consuming a healthy diet, particularly with sufficient intake of fruits and vegetables, is linked to higher life satisfaction 34,35,[38][39][40][41] .Good sleep quality is also a significant predictor of higher life satisfaction 34,39,41 .Engaging in and having an interest in daily activities was associated with higher life satisfaction among health professionals 34 .Finally, the absence of smoking was positively associated with higher life satisfaction 34,38,40,41 .Healthy lifestyle behaviors, such as healthy nutrition, stress management, regular exercise, spiritual well-being, and high-quality interpersonal relations, were related positively to life satisfaction in a sample of Turkish university students and staff 42 .However, these studies showed that healthy lifestyle behaviors and life satisfaction among university students and staff varied based on demographic variables, highlighting the need for targeted health strategies.

Health locus of control as a factor affected healthy behavior
Health-related locus of control (HLOC) refers to an individual's belief about the extent to which their health is controlled by internal factors (i.e., self), powerful others (e.g., doctors, physiotherapists), or chance (fate, case).People with an internal HLC believe that they can control events related to their life and health.In contrast, people with an external HLC believe that external factors, like chance or other people, determine their health and quality of life and are therefore not willing to take preventive actions 43 .Studies suggest that a higher Internal Health Locus of Control (I-HLOC) is associated with engaging in health-promoting behaviors, including physical activity, healthy diet, and adherence to medical advice [44][45][46][47] .Overall, people with an internal locus of control are more likely to eat well and exercise regularly and derive greater satisfaction from these activities 48 .Furthermore, I-HLOC is associated with better self-assessed health, physical health, mental health, and well-being [49][50][51] .In particular, a longitudinal study showed that a higher internal locus of control in childhood is a predictor of better health outcomes and behaviors in adulthood, including reduced risk of obesity and psychological distress 50 .The relationship between Powerful Others Health Locus of Control (P-HLOC) and health behaviors is more ambiguous and context-dependent.Some studies show that individuals who believe powerful others control their health engage in health-promoting behaviors, especially when influenced by healthcare professionals 44,47,52 .P-HLOC is particularly associated with preventive behaviors in patients with chronic diseases 52 .A high Chance Health Locus of Control (C-HLOC) is generally associated with poorer health behaviors, such as a lower likelihood of engaging in physical activity and healthy eating, as they believe their health is determined by fate 45,47,53 .
The key feature of a healthy lifestyle, a pattern of specific behaviors, is the ability to make choices.Healthrelated behaviors depend on beliefs regarding generalized expectations in three dimensions of locus of control 54,55 .Smoleń et al. 56 found that university students predominantly exhibit an internal locus of health control without significant gender differences.According to Wardle et al. 57 , students from Central and Eastern European countries showed lower levels of life satisfaction than their counterparts from the Western EU.Students with low levels of life satisfaction were convicted that their health is largely determined by chance.However, an overall high level of internal locus of health control was found in students from Central and East Europe, as compared to those from West 57 .Ghorbani-Dehbalaei et al. 58 showed that health literacy, health-related beliefs, and selfefficacy are essential factors for preventive behaviors among students.The internal health locus of control (HLC) promotes making independent decisions regarding one's health, that is, health-promoting behaviors, regardless of the influence of other people or environmental factors.It manifests itself in individuals taking responsibility for one's health.It is more beneficial from the point of view of public health policy 59 .

Theoretical background of the hypothetical research model on associations between HLOC, healthy behavior, and life satisfaction
Studies suggest that an internal health locus of control is generally associated with higher life satisfaction and better mental health 51,[60][61][62][63][64][65][66][67][68] .Popova 51 showed that higher levels of internal locus of control are related to healthier lifestyles, which in turn contribute to higher life satisfaction in young adults (aged between 19 and 30).During the COVID-19 pandemic, individuals with a high internal locus of control were also more likely to engage in pro-environmental behaviors, which also contributed to their life satisfaction 61 .Furthermore, physical activity and social interactions were found as pathways through which an internal locus of control can enhance life satisfaction 60 .Mei et al. 68 showed that both life satisfaction and a healthy lifestyle are positively associated with the internal HLC as well as the powerful others HLC, but chance HLC correlates negatively in a sample of Chinese students.
This study aims to examine the complex relationships between life satisfaction, health locus of control (HLC), and health behaviors among public health students, accounting for gender.Based on previous studies 51,60,61,68 we expect that HLC and healthy behavior determine life satisfaction, and healthy behavior plays a mediating role in the relationship between HLOC and life satisfaction.Several theories can explain the expected relationships between HLOC, healthy behaviors, and life satisfaction.The eudaimonic concept of happiness assumes that life satisfaction is a cognitive component of the quality of life.Eudaimonism, as a philosophical trend, assumes involvement in the axiological sphere.The most critical factors determining well-being are self-development, the ability to change one's life, striving to discover meaning in the actions undertaken, and fulfillment in pursuing the so-called purposeful good life 9,69 .Engagement in health-promoting behaviors can be considered as one of the challenges that increases self-development and leads to better physical and mental health, as well as higher well-being.It should be noted that health behaviors help to obtain the value of health, which facilitates success in life and achieving a high quality of life 70,71 .
The salutogenetic concept of health explains the relationship between health behaviors and the HLC as a process requiring decision-making and actions to maintain or build health 72 .This concept underlies contemporary health promotion, in which an essential element is emphasizing the ability to exercise control over one's health and that of others, which is important at both individual and systemic levels of public policy 73,74 .The attribution theory 75 assumes that HLOC serves as a crucial dynamic mechanism for motivating people to maintain healthy behaviors, which may lead to the development of life satisfaction.
The integration of all the theories mentioned above is possible from the perspective of living systems 76 .According to living systems analysis, Forrest 76 proposed that health arises from the specific hierarchical organization of interactions between various health assets, such as energetics, restoration, mind, reproduction, and capabilities, which collectively contribute to the development of adaptation, goal attainment, needs satisfaction, and survival.Health develops throughout the lifespan due to the dynamic, non-linear interactions between individuals and their environments.The attainment of well-being for individuals is not only impacted by their health but also determined by the goals they select to pursue based on their moral values, cultural background, preferences, aspirations, and temporal context.The present study demonstrates the interaction between the mind (defined as the capacity to receive, process, and interpret data from the internal and external environments to create information that can be stored as memories and used to formulate options for action plans) and capabilities (understood as an instrumental value of health in such behavioral domains that enable individuals to move around, communicate with others, care for oneself, and interact in social situations) among university students of various public health majors, in the Polish cultural context.Based on living systems model 76 , we assume the dynamic interactions between the mind (represented in this study by HLOC and life satisfaction cognitive assessment) and capabilities (as healthy behaviors) assets that lead to better adaptation and well-being.We presume that individuals with a strong sense of health control (mind) can better manage their health-promoting behaviors (capabilities), which ultimately contribute to better self-evaluation of life satisfaction (primarily health-related) and enhanced well-being.
Understanding the relationships in the assumed research model of mediation is the basis for taking individual responsibility for health and life satisfaction, which is beneficial from the point of view of public health.Students of various health fields should be role models for their future patients.Therefore, it is crucial to investigate health and well-being behaviors and beliefs in the public health student population.Our previous studies showed that healthy behaviors can play a mediating role in the relationship between optimism and life satisfaction in healthcare students 77 .In particular, positive mental attitudes, a component of healthy behaviors, mediate the relationship between optimism and life satisfaction 77 .However, the mediating role of healthy behaviors was never examined in the relationship between HLOC and life satisfaction among healthcare students.Previous research 68 has proven that a healthy lifestyle is a mediator in the relationship between HLOC in all scales (I-HLOC, P-HLOC, and C-HLOC) and life satisfaction in Chinese university students of various fields and majors.However, it is unclear whether the same associations would be observed among public health students in a different cultural context.The present study fills this gap and aims to examine the mediating effect of health behaviors in the relationship between health locus of control and life satisfaction among students of various public health majors from Poland.In the context of the previous research, the following hypotheses were formulated (Fig. 1): Women have higher levels of health behaviors than men 28 , while men have a higher level of I-HLOC than women 78 .
Health behaviors mediate the relationship between all three dimensions of HLC and life satisfaction 68 .

Sample characteristics and procedure
The cross-sectional study was performed at two large universities in Poland by using a paper-and-pencil questionnaire technique in an auditorium survey at the end of university lectures.The Research Ethics Committee approved the study protocol at the University of Opole, Poland (8/2020).The study followed the ethical requirements of anonymity and voluntariness of participation.Following the Helsinki Declaration, written informed consent was obtained from each university student before inclusion.The authors of the study received no specific funding for this work.
The research sample consists of 730 students aged between 19 and 30 (M = 22.29, SD = 1.64) from various majors related to medicine and health, like nursing, obstetrics, public health, medical rescue service, dietetics, and physiotherapy (Table 1).All participants attend the Medical University of Warsaw or the University of Rzeszów, Poland.The majority of this group are women and people with healthy body mass indexes (BMI), as determined by self-reported measurements of weight and height.

Health locus of control
The Multidimensional Health Locus of Control (MHLC) scale is designed to measure beliefs about an individual's health agency 79,80 .The 18-item questionnaire allows for the measurement of three dimensions of the health locus of control: internal (MHCL-I; e.g., "I am in control of my health"), powerful others (MHCL-P; e.g., "Whenever I don't feel well, I should consult a medically trained professional"), and chance (MHCL-C, e.g., "My good health www.nature.com/scientificreports/ is largely a matter of good fortune").Each subscale consists of six statements that participants grade on a scale from 1 (Strongly disagree) to 6 (Strongly agree).The total score on each scale is the sum of the scores from individual items.Original Cronbach's alfa coefficients were 0.77, 0.67, and 0.75 for each subscale, respectively 79 .The reliability of the Polish adaptation (Cronbach's α) was as follows: 0.74 for MHLC-I, 0.54 for MHLC-P, and 0.69 for MHLC-C 59 .In the present study, the Cronbach's alphas were 0.71, 0.68, and 0.73 for MHLC-I, MHLC-P, and MHLC-C, respectively.

Health behaviors
Health behaviors were assessed by the Health Behaviors Inventory (HBI) developed in the Polish language by Juczyński 59 .It consists of 25 statements describing various health-related behaviors.Participants rate the frequency of each behavior on a 5-point Likert scale (1 = Almost never, 2 = Rarely, 3 = From time to time, 4 = Often, and 5 = Nearly always).The instrument allows for the calculation of four subscales concerning different kinds of health behaviors: Healthy Diet (HD; e.g., "I eat a lot of vegetables and fruit"), Preventive Behavior (PB; e.g., "I undergo medical examinations regularly"), Positive Mental Attitudes (PMA; e.g., "I avoid situations that depress me"), and Healthy Practices (HP; e.g., "I sleep enough").The reliability coefficient (Cronbach's α) in the original study was 0.85 for the whole scale, and coefficients for the subscales were between 0.60 and 0.65 59 .Reliability coefficients in this study were Cronbach's α = 0.83 for the total HBI and 0.84, 0.55, 0.70, and 0.57 for the HD, PB, PMA, and HP scales, respectively.Because the reliability of the PMA and HP scales was insufficient, only the total HBI score will be tested in further statistical analyses.

Satisfaction with life
The dependent variable, life satisfaction, was measured using the Satisfaction with Life Scale (SWLS) created by Diener et al. 7 .It is a short 5-item scale (e.g., "In most ways my life is close to my ideal") with a seven-point Likert-type answer scale (ranging from 1 = Strongly disagree to 7 = Strongly agree).The total score is calculated as a sum of all five items and ranges between 5 and 35, with higher scores meaning greater life satisfaction.The reliability assessed by Cronbach's α was 0.81 in the Polish adaptation 59 and 0.83 in the current study.

Statistical analyses
Descriptive statistics, like ranges, mean (M), standard deviation (SD), median (Mdn), skewness, and kurtosis, were performed as a preliminary analysis to examine the parametric properties of the data (Table 2).Since the sample size was large (N = 730) and skewness and kurtosis ranged between − 1 and + 1, a normal data distribution is considered, so parametric statistical tests were performed in the next part of the study.Gender differences were assessed using the independent samples Student's t-tests, with Cohen's d for an effect size assessment.Pearson's r-test of correlations was performed to examine associations between variables.The mediation analysis was performed to test the indirect effect of internal health locus of control on life satisfaction among public health students via health behaviors.Gender was included in the analysis as a covariate.Bootstrapping with 5000 replications was used to increase the accuracy of results.All analyses were performed using IBM SPSS Statistics (version 26) 81 .Mediation analysis was conducted using PROCESS ver.3.5 macro for SPSS, designed by Hayes 82,83 .

Descriptive statistics
Descriptive statistics for life satisfaction (SWLS), healthy behavior (HBI), and three scales of health locus of control (MHLC-I, MHLC-P, and MLHC-C) are presented in Table 2.Among the three sales of HLOC, the highest scores were presented in I-HLOC, while the lowest was in P-HLOC.Students showed the highest scores Associations between variables were examined using Pearson's correlations (Table 3) as a preliminary analysis.Life satisfaction is positively related to health behaviors and internal HLOC.Health behaviors are related positively to both I-HLOC and P-HLOC but negatively to C-HLOC.Among HLOC scales, I-HLOC is associated positively with P-HLOC, and P-HLOC is related positively to C-HLOC.
Life satisfaction, healthy behavior, and three scales of health locus of control were compared across men and women, using independent samples Student's t-test (Table 4), to verify hypothesis H1.Women are engaged in health behaviors significantly more often than men.In particular, women outperform men in a healthy diet  www.nature.com/scientificreports/and preventive behavior.When it comes to the HLOC, women scored higher than men in P-HLOC, while men scored higher in I-HLOC than women.However, the effect size for all gender differences was small (Table 3).

Mediation analysis
A mediation analysis assumes that the total effect is significant.Since powerful others HLC and chance HLC were unrelated to life satisfaction (Table 3), the mediation analysis was not conducted for these two variables (the total effect was insignificant).Therefore, the mediation analysis was performed only once to examine the mediating effect of health behaviors on the relationship between internal HLC and life satisfaction among healthcare students.Gender was included in the mediation model as a confounder variable.The results are shown in Table 5 and Fig. 2. The total effect of internal HLC on life satisfaction was significant, but gender was not related to this association, R 2 = 0.01, F(2, 727) = 3.95, p = 0.020.I-HLOC (β = 0.29, p < 0.001) and male gender (β = − 0.19, p < 0.001) were significant predictors of health behaviors, R 2 = 0.11, F(2, 727) = 44.32,p < 0.001.Also, health behaviors (β = 0.42, p < 0.001) and female gender (β = 0.08, p = 0.024) were predictors of life satisfaction, R 2 = 0.17, F(3, 726) = 49.63,p < 0.001.When a mediator (health behaviors) was included in the analysis, the association between I-HLOC and life satisfaction decreased almost to zero.It was insignificant, indicating that healthy behavior fully mediates the relationship between I-HLOC and life satisfaction.

Discussion
The study revealed that gender plays a role in distinguishing the participants' health behaviors and health locus of control.In general, women tend to exhibit greater levels of health behaviors.However, it is crucial to consider the variations among different categories of such behaviors.Women exhibit distinctive patterns in their nutritional habits and proactive measures, with cultural factors being considered the primary driver of these differences.A woman is typically expected to manage the organization of family life.One way in which she fulfills this responsibility is by displaying concern for the well-being of her family members through actions such as preparing meals and engaging in preventive behavior, including arranging for medical check-ups.Furthermore, the role of motherhood often motivates women to prioritize their health and wellness 84,85 Previous research indicates that men typically engage in higher levels of physical activity than women 86 .Consequently, each gender constructs its lifestyle differently.
Our investigation further verifies that men possess greater internal control over their health, while women rather believe their health depends on healthcare experts.According to a study conducted by researchers from the same cultural background, the health locus of control appears to be unrelated to gender 78 .Fiszer and Sobów's 87 research indicates that students attending medical universities (primarily women) scored higher in an external locus of health control than students of other universities.Overall, men outperform women in an internal HLC.It is conceivable that individuals who engage in deliberate learning may devote all available resources to their well-being.Nevertheless, this is not always the case, as functioning within a medical and paramedical environment may foster a biomedical approach to health, which involves extensive reliance on the healthcare system and thus limits individual accountability for one's health.Shin and Lee 88 reported a correlation between a lack of internal locus of control in unmarried women in their 20 s and an increased incidence of mental health problems.
Researchers recommend that young individuals cultivate internal health control in their daily lives.By managing mental health challenges, individuals can enhance their life satisfaction.This study showed that high levels of healthy behaviors are associated with increased life satisfaction in the group of public health students.The present findings confirm previous studies performed in various subgroups and populations [33][34][35][36][37][38][39][40][41][42]66,68 . It shuld be emphasized that young adults often exhibit behaviors that may not be conducive to good health (e.g., smoking, excessive consumption of alcohol or psychoactive substances, and engaging in unhealthy lifestyle habits).The pursuit of effective methods for fostering healthy behaviors has been a longstanding endeavor in Western societies, as research unequivocally demonstrates that modifications in health practices result in enhanced subjective well-being 33,89 .Life satisfaction is positively associated with various health-promoting behaviors such as abstaining from smoking, engaging in regular physical activity, utilizing sun protection, consuming fruits, and limiting fat intake 38,90 .The longitudinal study evidenced that health-promoting behaviors are a predictor of subjective well-being 91 .People who are characterized by a high level of life satisfaction are more likely to perceive their lives as pleasant, valuable, and meaningful.
Health behaviors are determined by the culture in which a person lives.Health competencies obviously play a significant role in maintaining a healthy lifestyle, prevention, and health promotion, but they are also significantly related to life satisfaction 92 .It, therefore, seems that systemic educational activities in the above area, undertaken during studies at the university, should constitute a standard element of education, as they can significantly increase the resources of broadly understood well-being necessary for effective functioning.Grace-Farfaglia et al. 93 indicate that practicing a healthy lifestyle affects life satisfaction, especially in men.Our research shows that it is worth developing awareness of the individual impact on one's health and creating positive attitudes towards health and working on it.
In accordance with other research 51,[60][61][62][63][64][65][66][67][68] , the present study has revealed a positive association between life satisfaction and the internal health locus of control.However, P-HLOC and C-HLOC were unrelated to life satisfaction in this study.Previous studies showed inconsistency in the relationship between external HLOC and well-being.For example, the belief in chance and powerful others was unrelated to life satisfaction among Polish residents of veteran homes for the elderly 62 , which seems in line with this study.In contrast, Mei 68 found a positive relationship of life satisfaction with both I-HLOC and P-HLOC and a negative association with C-HLOC among Chinese university students.The belief that powerful others controlling health may negatively affect life satisfaction among both older adults and those with chronic conditions 66,67 .Aso, Abu-Bader et al. 94 proved that locus of control, as well as perceived physical health, social support, and emotional balance, are significant predictors of life satisfaction among older people.However, in older adults, the relationship between health locus of control and life satisfaction was influenced by factors such as health status and income, but internal control remains a significant predictor of life satisfaction independent of these factors 64 .The studies mentioned above and our findings collectively suggest that I-HLOC can play a crucial role in well-being formation.
The internal HLC, as an element determining life satisfaction, is associated with having control over and managing one's life.The best area to train life management skills is free time.In general, the use of free time, an area that young people particularly like to decide about, is positively correlated with higher life satisfaction, especially in the case of rare forms of recreation and unusual experiences 95 .The leisure time area is usually the one that fully depends on our decisions and has consequences for maintaining health.Research shows that leisure satisfaction increases the level of overall life satisfaction 96 .As Busseri and Samani 12 claim, much depends on the individual set of beliefs, which change across age and experience and are also subject to change during the period of education.Some researchers argue that students are a special group, and it is worth focusing on interventions that increase the level of health behaviors.The stage of life they are in is the most suitable for promoting a healthy lifestyle 97 .Therefore, it seems crucial to invest in social skills training and provide students with opportunities to play leadership roles in various organizations, clubs, and associations.It is also essential that at each level of studies, academic teachers use activating methods and various forms of learning, thanks to which students can experience taking responsibility for their development process.Special events and dedicated health programs that promote healthy behaviors and strengthen internal HLC may also be helpful 98 .Public health study programs should include subjects related to health education, health promotion, and health training.
The current research demonstrates that the existing theoretical framework within the living systems perspective 76 can account for the process of enhancing life satisfaction through healthy behaviors among individuals with an internal health locus of control.In line with previous studies, 51,60,61,68 , the current study proved that health behaviors may play a mediator role in the relationship between internal health locus of control and life satisfaction.However, for the first time, these associations were examined in a sample of Polish students who were majoring in healthcare.In a similar study, Mei et al. 68 showed that all three dimensions of HLC are significant predictors of both health behaviors and life satisfaction.It is important to note that there are notable differences in the research settings in the previous 68 and our studies, including various countries, traditions, and cultures (e.g.,China with Confucianism and Poland with European culture), affecting lifestyle.Moreover, students from China were involved in various academic fields 68 , whereas participants in the current study were enrolled in fields related to healthcare.The current study's findings emphasize the significance of exercising internal control over one's health and adopting healthy lifestyle habits, which support the majority of previous findings 51,60,61,68 .These behaviors can lead to greater enjoyment of life.Contemporary notions of health prioritize fostering the capacity for action and adaptability.Health is established through the dynamic interactions between individuals and their environment 76 .The study adds to the existing literature support for the living systems theory 76 , showing the www.nature.com/scientificreports/specific interactions between mind assets concerning the sense of HLOC and capabilities assets in the healthy behaviors dimensions, which can increase the subjective sense of well-being regarding life satisfaction.

Limitations of the study
This study may have some limitations related to the application of the results to the general population.The research was conducted in a specific region of Central and Eastern Europe.The research sample comes from two large universities in the eastern part of Poland, so the results obtained can be applied with some caution to the national student population.Cultural diversity of health behaviors and lifestyle determinants should be taken into account, even in specific regions of a given country.Given the cross-sectional design of this study, causality should be treated with caution.It would certainly be worth conducting longitudinal studies taking into account the cultural and socioeconomic diversity of European regions.In this type of research, there is also a problem with accurately capturing many interrelated health behaviors that make up lifestyle.The present study is based on self-report measures.Future studies should replicate the present study using a research tool that comprehensively and more objectively measures a representative set of health behaviors.

Conclusions
Pro-health behaviors should be promoted among young adults, especially in men, as constructive ways to increase quality of life.This study confirmed the existence of a mechanism through which an internal sense of control over health influences life satisfaction through health-related behaviors in a sample of Polish university students of various healthcare majors.The findings support the living systems theory, adding to existing knowledge a piece of novel evidence.It is particularly important to strengthen internal HLC, especially in women, through appropriate social skills training.Systemic education in the public health area seems necessary, shaping specific beliefs about health and taking responsibility for them because health behaviors are an essential mediator in the relationship between the internal HLC and life satisfaction.

Figure 1 .
Figure 1.The mediating effect of health behaviors on the relationships between health locus of control (HLC) and life satisfaction (hypothetical model of mediation).

Table 1 .
Sample characteristics.inhealthy diet but the lowest in healthy practices, taking into account health behaviors.The mean score of life satisfaction indicates the respondents are slightly satisfied with their lives.